/*
 * Created on 17 Sep 2007
 * Created by Allan Crooks
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package com.aelitis.azureus.core.peermanager.messaging.bittorrent.ltep;

import org.gudy.azureus2.core3.util.DirectByteBuffer;

import com.aelitis.azureus.core.peermanager.messaging.Message;
import com.aelitis.azureus.core.peermanager.messaging.MessageException;
import com.aelitis.azureus.core.peermanager.messaging.MessageManager;
import com.aelitis.azureus.core.peermanager.messaging.bittorrent.BTMessageDecoder;
import com.aelitis.azureus.core.util.CopyOnWriteMap;

/**
 * @author Allan Crooks
 * 
 */
public class LTMessageDecoder extends BTMessageDecoder {

    private static CopyOnWriteMap<Byte, byte[]> default_entension_handlers = new CopyOnWriteMap<Byte, byte[]>();

    public static void addDefaultExtensionHandler(long id, byte[] message_id) {
        default_entension_handlers.put((byte) id, message_id);
    }

    public static void removeDefaultExtensionHandler(long id) {
        default_entension_handlers.remove((byte) id);
    }

    private CopyOnWriteMap<Byte, byte[]> extension_handlers = new CopyOnWriteMap<Byte, byte[]>();

    public LTMessageDecoder() {
        if (default_entension_handlers.size() > 0) {

            extension_handlers.putAll(default_entension_handlers);
        }
    }

    protected Message createMessage(DirectByteBuffer ref_buff) throws MessageException {
        // Check to see if it is a LT-extension message. If not, delegate to BTMessageDecoder.
        int old_position = ref_buff.position(DirectByteBuffer.SS_MSG);
        byte id = ref_buff.get(DirectByteBuffer.SS_MSG);
        if (id != 20) {
            ref_buff.position(DirectByteBuffer.SS_MSG, old_position);
            return super.createMessage(ref_buff);
        }

        // Here is where we decode the message.
        id = ref_buff.get(DirectByteBuffer.SS_MSG);
        switch (id) {
            case 0:
                return MessageManager.getSingleton().createMessage(LTMessage.ID_LT_HANDSHAKE_BYTES, ref_buff, (byte) 1);
            case 1:
                return MessageManager.getSingleton().createMessage(LTMessage.ID_UT_PEX_BYTES, ref_buff, (byte) 1);
            case 3:
                return MessageManager.getSingleton().createMessage(LTMessage.ID_UT_METADATA_BYTES, ref_buff, (byte) 1);
            case 4:
                return MessageManager.getSingleton().createMessage(LTMessage.ID_UT_UPLOAD_ONLY_BYTES, ref_buff, (byte) 1);
            default: {
                byte[] message_id;

                message_id = extension_handlers.get(id);

                if (message_id != null) {
                    return MessageManager.getSingleton().createMessage(message_id, ref_buff, (byte) 1);
                }
                System.out.println("Unknown LTEP message id [" + id + "]");
                throw new MessageException("Unknown LTEP message id [" + id + "]");
            }
        }
    }

    public void addExtensionHandler(byte id, byte[] message_id) {
        extension_handlers.put(id, message_id);
    }

    public void removeExtensionHandler(byte id) {
        extension_handlers.remove(id);
    }
}
